US 7115984 B2
A semiconductor device package is disclosed which is substantially die-sized with respect to each of the X, Y and Z axes. The package includes outer connectors that are located along at least one peripheral edge thereof and that extend substantially across the height of the peripheral edge. Each outer connector is formed by severing a conductive via that extends substantially through a substrate blank, such as a silicon wafer, at a street located adjacent to an outer periphery of the semiconductor device of the package. The outer connectors may include recesses that at least partially receive conductive columns protruding from a support substrate therefor. Assemblies may include the packages in stacked arrangement, without height-adding connectors.
1. A semiconductor device package, comprising:
a semiconductor device including at least one bond pad on an active surface thereof and at least one recess in a peripheral edge thereof;
at least one outer connector corresponding to the at least one bond pad, the at least one outer connector positioned at least partially within the at least one recess and having a height that extends substantially along a height of the peripheral edges, the at least one outer connector comprising:
opposite surfaces exposed at the active surface and a back side of the semiconductor device: and
a recess extending substantially from one of the opposite surfaces to another of the opposite surfaces: and
at least one conductive trace extending between the at least one bond pad and the at least one outer connector.
2. The semiconductor device package of
an insulative layer positioned beneath at least the at least one conductive trace.
3. The semiconductor device package of
an insulative layer positioned over at least the at least one conductive trace and the at least one bond pad.
4. The semiconductor device package of
a back side insulative layer substantially covering a back side of the semiconductor device.
5. The semiconductor device package of
6. The semiconductor device package of
7. The semiconductor device package of
8. The semiconductor device package of
9. The semiconductor device package of
10. The semiconductor device package of
This application is a divisional of application Ser. No. 10/183,820 filed Jun. 27, 2002, now U.S. Pat. No. 6,727,116, issued Apr. 27, 2004.
1. Field of the Invention
The present invention relates generally to packaged semiconductor devices with a low profile. More specifically, the invention pertains to wafer-level packages having a true chip profile or both a chip profile and a chip footprint.
The dimensions of many different types of state-of-the-art electronic devices are ever decreasing. To reduce the dimensions of electronic devices, the structures by which the microprocessors, memory devices, other semiconductor devices, and other electronic components of these devices are packaged and assembled with carriers, such as circuit boards, must become more compact. In general, the goal is to economically produce a chip-scale package (CSP) of the smallest size possible, and with conductive structures, such as leads, pins, or conductive bumps, which do not significantly contribute to the overall size in the X, Y, or Z dimensions, all while maintaining a very high performance level.
One approach to reducing the sizes of assemblies of semiconductor devices and circuit boards has been to minimize the profiles of the semiconductor devices and other electronic components upon carrier substrates (e.g., circuit boards) so as to reduce the distances the semiconductor devices protrude from the carrier substrates. Various types of packaging technologies have been developed to facilitate orientation of semiconductor devices upon carrier substrates in this manner.
Conventionally, semiconductor device packages are multilayered structures, typically including a bottom layer of encapsulant material, a carrier (e.g., leads, a circuit board, etc.), a semiconductor, die, and a top layer of encapsulant material, for example. In addition, the leads, conductive bumps, or pins of conventional semiconductor device packages, which electrically connect such packages to carrier substrates, as well as provide support for the packages, are sometimes configured to space the semiconductor device packages apart from a carrier substrate. As a result, the overall thicknesses of these semiconductor device packages and the distances the packages protrude from carrier substrates are greater than is often desired for use in state-of-the-art electronic devices.
Wafer-level packaging (WLP) refers to packaging of an electronic component while it is still part of a wafer. The packages that are formed by WLP processes are generally considered to be “chip-sized” packages, at least with respect to the lateral X and Y dimensions, i.e., “footprint”, but typically have somewhat enlarged profiles in the Z dimension due to the solder balls, pins, or other conductive structures that protrude therefrom. Likewise, modules of stacked dice may use interdie connections comprising solder balls, pins, etc., which substantially contribute to the overall Z dimension, i.e., profile.
“Flip-chip” technology, as originating with controlled-collapse chip connection (C-4) technology, is an example of an assembly and packaging technology that results in a semiconductor device being oriented substantially parallel to a carrier substrate, such as a circuit board. In flip-chip technology, the bond pads or contact pads of a semiconductor device are arranged in an array over a major surface of the semiconductor device. Flip-chip techniques are applicable to both bare and packaged semiconductor devices. A packaged flip-chip type semiconductor device, which typically has solder balls arranged in a so-called “ball grid array” (BGA) connection pattern, typically includes a semiconductor die and a carrier substrate, which is typically termed an “interposer”. The interposer may be positioned adjacent either the back side of the semiconductor die or the active (front) surface thereof.
When the interposer is positioned adjacent the back side of the semiconductor die, the bond pads of the semiconductor die are typically electrically connected by way of wire bonds or other intermediate conductive elements to corresponding contact areas on a top side of the interposer. These contact areas communicate with corresponding bumped contact pads on the back side of the interposer. This type of flip-chip assembly is positioned adjacent a higher-level carrier substrate with the back side of the interposer facing the carrier substrate.
If the interposer is positioned adjacent the active surface of the semiconductor die, the bond pads of the semiconductor die may be electrically connected to corresponding contact areas on an opposite, top surface of the interposer by way of intermediate conductive elements that extend through one or more holes formed in the interposer. Again, the contact areas communicate with corresponding contact pads on the interposer. In this type of flip-chip semiconductor device assembly, however, the contact pads are also typically located on the top surface of the interposer. Accordingly, this type of flip-chip assembly is positioned adjacent a higher-level carrier substrate, such as a printed circuit board, by orienting the interposer with the top surface facing the carrier substrate.
In each of the foregoing types of flip-chip semiconductor devices, the contact pads of the interposer are disposed in an array that has a footprint that mirrors an arrangement of corresponding terminals or other contact regions formed on a carrier substrate. Each of the bond (on bare flip-chip semiconductor dice) or contact (on flip-chip packages) pads and its corresponding terminal may be electrically connected to one another by way of a conductive structure, such as a solder ball, that also spaces the interposer some distance away from the carrier substrate.
The space between the interposer and the carrier substrate may be left open or filled with a so-called “underfill” dielectric material that provides additional electrical insulation between the semiconductor device and the carrier substrate. In addition, each of the foregoing types of flip-chip semiconductor devices may include an encapsulant material covering portions or substantially all of the interposer and/or the semiconductor die.
The thicknesses of conventional flip-chip type packages having ball grid array connection patterns are defined by the combined thicknesses of the semiconductor die, the interposer, the adhesive material therebetween, and the conductive structures (e.g., solder balls) that protrude above the interposer or the semiconductor die. As with the flat packages, conventional flip-chip type packages are often undesirably thick for use in small, thin, state-of-the-art electronic devices. Furthermore, use of this general construction method for producing a stacked multichip module (MCM) results in a relatively high-profile, large footprint device.
Thinner, or low-profile, flip-chip type packages have been developed which include interposers or other carriers with recesses that are configured to receive at least a portion of the profiles of semiconductor devices. While interposers that include recesses for partially receiving semiconductor devices facilitate the fabrication of thinner flip-chip type packages, the semiconductor dice of these packages, as well as intermediate conductive elements that protrude beyond the outer surfaces of either the semiconductor dice or the interposers, undesirably add to the thicknesses of these packages.
U.S. Pat. Nos. 5,541,450 and 5,639,695, both issued to Jones et al. (hereinafter “the '450 and '695 patents”), disclose another type of flip-chip type package, which includes an interposer with a semiconductor die receptacle extending completely therethrough. The '695 patent teaches a package that may be formed by securing a semiconductor die directly to a carrier substrate and electrically connecting the interposer to the carrier substrate before the semiconductor die is electrically connected to the interposer. The semiconductor die, intermediate conductive elements that connect bond pads of the semiconductor die to corresponding contact areas on the interposer, and regions of the interposer adjacent the receptacle may then be encapsulated. While this method results in a very low-profile flip-chip type package, the package cannot be tested separately from the carrier substrate. As a result, if the package is unreliable, it may also be necessary to discard the carrier substrate and any other components thereon. Moreover, the packaging method of the '695 patent complicates the process of connecting semiconductor devices and other electronic components to a carrier substrate. In addition, it should be noted that in order to obtain a low-profile package, it may be necessary to sacrifice footprint compactness. The footprint area of such a low-profile package may be significantly greater than the area of the semiconductor die thereof.
Thus, there is a need for semiconductor device packages that have dimensions that closely resemble the corresponding dimensions of a semiconductor device of such packages, as well as for packaging methods.
In the present invention, semiconductor devices include bond pads, or outer connectors, that are located on one or more peripheral edges thereof. The outer connectors, which facilitate electrical connection of the semiconductor device to a substrate, such as a test substrate or a carrier substrate (e.g., an interposer or a printed circuit board), may be arranged on a peripheral edge of the semiconductor device in such a way as to impart the semiconductor device with a castellated appearance. Optionally, the outer connectors may include recesses that extend substantially from one major surface of the semiconductor device to another, opposite major surface of the semiconductor device.
By way of example only, the outer connectors may be fabricated by forming redistribution circuitry over active surfaces of semiconductor devices that have yet to be severed from a fabrication substrate, such as a full or partial wafer of semiconductive material (e.g., silicon, gallium arsenide, indium phosphide, etc.) or a full or partial, so-called silicon-on-insulator (SOI) type substrate (e.g., a silicon-on-ceramic (SOC) substrate, silicon-on-glass (SOG) substrate, silicon-on-sapphire (SOS) substrate, etc.). The redistribution circuitry extends from bond pad locations on the active surface of each semiconductor device on the fabrication substrate to a boundary, or “street”, between that semiconductor device and an adjacent semiconductor device. At the boundary, electrically conductive vias which extend substantially through the thickness of the substrate are formed. The electrically conductive vias may comprise a solid quantity of conductive material or have hollow portions extending substantially along the lengths thereof. Upon severing the adjacent semiconductor devices from one another, which is typically referred to in the art as “dicing”, each conductive via is bisected, creating outer connectors that are positioned on the resulting peripheral edge of the singulated or diced semiconductor device.
As outer connectors formed in this manner extend substantially from an active surface to the back side of the semiconductor device, portions of each outer connector may be exposed at both the active surface and the back side of the semiconductor device. Accordingly, either the active surface or the back side of a semiconductor device of the present invention may be joined and electrically connected to one or more other semiconductor devices or semiconductor device components (e.g., test substrates, carrier substrates, etc.).
Assembly of a semiconductor device according to the present invention with another semiconductor device or semiconductor device component may be accomplished without any significant intervening space between the assembled semiconductor devices or semiconductor device and semiconductor device component. In assembling a semiconductor device of the present invention with another semiconductor device or a semiconductor device component, the outer connectors of the semiconductor device and corresponding contacts of the other semiconductor device or semiconductor device component are aligned, then electrically connected with one another. Accordingly, semiconductor devices that include such outer connectors may facilitate the formation of assemblies and packages with minimal footprints (X and Y dimensions) as well as a minimal profile (Z dimension).
An example of a semiconductor device assembly that may include more than one semiconductor device that incorporates teachings of the present invention may comprise a so-called “multiple-chip module” of stacked configuration. Aligned, corresponding outer connectors of the two or more stacked semiconductor devices may be conductively connected to one another, such as by solder or by conductive pins or other structures that are at least partially received within receptacles of the outer connectors. As the outer connectors extend from the active surface to the back side of each of the semiconductor devices and since electrical connection may be effected at the peripheries of the semiconductor devices, the opposed back side and active surface of adjacent semiconductor devices may be positioned very closely to one another. Thus, a multichip module according to the present invention may comprise a stack of a large number of dice or packages, while avoiding the use of undesirable height-adding interdie connectors, such as solder balls, bond wires, and the like. As a result, a multichip module that includes semiconductor devices of the present invention may have a minimum profile dimension (Z dimension).
Additionally, a multichip module that includes semiconductor devices according to the present invention may include a support substrate which has a footprint which is substantially equal in size (i.e., X and Y dimensions) to or only slightly larger than the footprint of the remainder of the multichip module. The support substrate may include conventional contacts (e.g., bond pads if the support substrate is an interposer or another semiconductor device, terminals if the support substrate is a circuit board, contact areas on leads if the support substrate comprises leads, etc.) to which outer connectors of the semiconductor devices are electrically connected. By way of example only, each contact of the support substrate and the corresponding outer connectors of the semiconductor devices may be electrically connected to one another (e.g., secured to a contact of the support substrate and located between adjacent surfaces of corresponding, adjacent outer connectors and/or within recesses of corresponding, adjacent outer connectors) by way of a conductive material (e.g., solder, a conductive or conductor-filled elastomer, etc.), by way conductive pins or other elongate conductive structures (e.g., upwardly standing wires) that are secured to and protrude from the contact and that are at least partially received within receptacles of the corresponding outer connectors, or otherwise, as known in the art.
Other features and advantages of the present invention will become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims.
In the drawings, in which some dimensions may be exaggerated, exemplary embodiments for carrying out the invention are illustrated:
Semiconductor devices 16 and, thus, assembled packages 10 that include semiconductor devices 16, may comprise any type of device, such as a memory device (e.g., dynamic random access memory (DRAM), static random access memory (SRAM), programmable memory (PROM), electrically erasable programmable memory (EEPROM), flash memory, etc.), a processor, or any other type of semiconductor device known in the art. Semiconductor device 16 includes bond pads 20 (see, e.g.,
The fabrication of semiconductor devices 16 may be effected in accordance with the desired end use of the assembled package 10 of which each semiconductor device is intended to be a part. An integrated circuit (not shown) is formed in each semiconductor device. 16 to interface with the active surface 18, as known in the art. A wide variety of integrated circuit device elements may be used in the semiconductor device 16 of a package 10, including, for example, conductors, resistors, transistors, capacitors, inductors, insulators, and the like. Fabrication processes are used which typically fall into the groups known as layering, patterning, doping and heating, and many specific variations of each are well known. For example, useful layering processes include various methods of oxidation, chemical vapor deposition (CVD), molecular beam epitaxy, physical vapor deposition (PVD), and other techniques.
In the exemplary embodiment depicted in
In addition to a semiconductor device 16 (
Singulation of the packages 10 from one another and from the substrate blank 8 is effected by cutting the substrate blank 8 along boundary lines 12 and 14 thereon. As substrate blank 8 is cut along streets 12 and 14, the full conductive vias 30 that are positioned on a cut street 12, 14 are cut into outer connectors 31, which remain at the peripheral edges 22 of each of the singulated packages 10, as shown in
Also, as shown in
Turning now to
The conductive traces 28 may be formed by a wide range of processes known in the art. By way of example, one or more layers of conductive material, such as metal (e.g., aluminum, copper, gold, nickel, etc.), may be formed on package tops 32 by any suitable process, including, without limitation, chemical vapor deposition (CVD), physical vapor deposition (PVD) (e.g., sputtering or evaporation), electrolytic plating, electroless plating, and immersion plating techniques. While such a layer of conductive material may be formed before, simultaneously with, or following the introduction of conductive material into via through-holes 38 (see, e.g.,
For example, in
As depicted in
Referring again to
The via through-holes 38 may be formed by any of a variety of known processes, depending upon their heights 70 (i.e., the thickness of the substrate blank 8 and, thus, of the packages 10 in and between which the via through-holes 38 are to be formed) (see
Once the via through-holes 38 are formed, exposed semiconductive material at the surfaces thereof may be coated with an insulative lining 39. The insulative lining 39 may be formed by known processes, such as by exposure of the surfaces of via though-holes 38 to oxidizing conditions, deposition of an insulative material (e.g., silicon dioxide, silicon nitride, silicon oxynitride, etc.) onto the surfaces of via through-holes 38, or any other suitable, known process.
As depicted in
As shown in
Turning again to
A package 10 with castellated edges 22, 24 and outer connectors 31 of the type described herein has an extremely low profile, which may be only slightly larger than that of the semiconductor device 16 of such a package 10. Furthermore, such a package 10 has a minimal footprint, which closely resembles the footprint of the semiconductor device 16 thereof. In addition, due to its minimized size, the lengths of conductive traces 28 that are required to redistribute the input/output provided by bond pads 20 to outer connectors 31 are minimized, facilitating the provision of a package 10 with electrical characteristics and signal integrity that are superior to those of existing semiconductor device packages.
In another aspect of the present invention, a plurality of packages 10 may be assembled to form a so-called multichip module (MCM). In a stacked MCM according to the present invention, packages 10 may be positioned adjacent to one another with little or no spacing therebetween, as may result from the use of discrete conductive elements, such as solder balls, between adjacent packages, and with a minimized footprint, in contrast to the expanded footprints that are required when laterally extending, intermediate conductive elements, such as bond wires, conductive tape-automated bonding (TAB) elements carried upon a dielectric polymer film, leads, or the like, are used to provide electrical connections in conventional MCMs.
As depicted in
It will be appreciated that the multichip module 90 shown in
As shown, the packages 10 may be electrically interconnected and physically supported by way of conductive columns 88 that are configured and arranged to be at least partially received within aligned recesses 40 of corresponding sets of outer connectors 31 of the stacked packages 10. Conductive columns 88 are elongate members that may be formed from a conductive material (e.g., aluminum, copper, etc.) which will substantially retain their shapes when the outer connectors 31 of packages 10 are positioned adjacent thereto. Thus, each conductive column 88 acts as a common lead for each of the outer connectors 31 of a set.
Each conductive column 88 is secured to (e.g., by solder, reflowing a portion thereof to secure the same to a terminal, etc.) and protrudes from a corresponding conductive member 100 (e.g., a terminal, conductive material-lined recess, etc.) of a support substrate 82 of the multichip module 90. In the exemplary embodiment of a circuit board (e.g., FR-4 resin, BT resin, etc.) type support substrate 82 depicted in
As an example of a method for forming the conductive columns 88, a wire (e.g., a gold or aluminum wire) may be drawn by use of a wire bonding capillary, as known in the art. Such a wire may have a generally circular cross-section, although conductive columns 88 having any other suitable cross-section, taken transverse to the lengths thereof, are also within the scope of the present invention. By way of example only, and as shown in
As noted above, the conductive column 88′ may have transverse cross-sectional dimensions (e.g., a diameter 102) that substantially match or are slightly smaller than the complementary dimensions (e.g., a diameter 41;
As shown in
If desired (e.g., in packages that include outer connectors 31 arranged along only one or two adjacent peripheral edges 22, 24 thereof), conductive columns 88 may be secured to their outer connectors 31. One example of the manner in which a conductive column 88 may be secured to a set of corresponding outer connectors 31 includes the use of a conductive adhesive, such as solder, another metal or metal alloy, a conductive or conductor-filled elastomer, or the like, which may be positioned between a conductive column 88 and each of its corresponding outer connectors 31, around an outer periphery of the conductive column 88 and in contact with lateral edges of each of the outer connectors 31 that corresponds thereto, or in a combination of these locations. Optionally, the conductive columns 88 may be coated with tin to enhance connection to the outer connectors 31 in this manner. As another example, a nonconductive material may be disposed around a surface of each conductive column 88 that does not contact outer connectors 31, as well as to a peripheral edge 22, 24 of each package 10 of the multichip module 90, to maintain contact and, thus, an electrical connection between each conductive column 88 and its corresponding outer connectors 31.
Of course, when support substrate 82 comprises a test substrate, it may not be desirable to bond or otherwise permanently secure the conductive columns 88 to their corresponding outer connectors 31, as temporary, reversible electrical connections are desired.
Following assembly of the support substrate 82 with all the packages 10 in the stack and the establishment of contact between conductive columns 88 and corresponding sets of outer connectors 31, the conductive columns 88 may be cut, or trimmed, to remove any excess portion extending beyond the uppermost package 10. The conductive columns 88 may alternatively be provided with a length that corresponds to the height at which packages 10 are to be stacked in the multichip module 90.
As described above, the multichip module 90 may be readily fabricated using processes and equipment which are widely used or known in the electronics industry. The package 10 of the present invention may have a total thickness of less than about 1 mm, making the package 10 suitable for use in compact electronic devices, such as cellular telephones, handheld computers, and portable computers, where such low profile packages are required or desired. The multichip module 90, of the invention will likewise have a relatively low profile, making it suitable for the same types of devices.
Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present invention, but merely as providing illustrations of some exemplary embodiments. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Features from different embodiments may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions, and modifications to the invention, as disclosed herein, which fall within the meaning and scope of the claims are to be embraced thereby.